1. The Evolution of Cooperation in Structured Animal Societies. Cooperation involves one individual paying a cost so another can receive a benefit. It is thus open to exploitation by cheats who do not reciprocate cooperative acts. Whilst cooperation among kin can be explained by kin selection, many social animals live in dynamic societies where individuals regularly move between groups and cooperate with non-kin. This presents us with an evolutionary conundrum. A significant limitation of much of the current work on this topic is that it is driven by theoretical approaches and we currently lack empirical tests of key predictions and assumptions in real world populations.We are studying the role of population social structure in maintaining cooperation among non-kin using the Trinidad guppy (Poecilia reticulata) as a model system.

2. The Evolution of Prolonged Post-Reproductive Lifespan in a Non-Human Mammal

Understanding why females stop reproduction prior to the end of their lives is a key objective in the biological, medical and social sciences. In traditional human societies for example, women typically have their last child at 38 but may live for a further 20 years or so. This phenomenon is by no means restricted to humans and across many species of mammals, birds and fish, females may have a lifespan that extends far beyond their last birth. Currently however, almost nothing is known about the forces that have shaped the post-reproductive lifespan in non-human animals that live in close-knit family groups. In this project we are studying two populations of killer whales Orcinus orca that live off the coast of North America. Killer whales have the longest post-reproductive lifespan of all non-human animals; females stop reproducing in their 30s-40s but can survive into their 90s. We are using data collected over the last three decades during which time more than 600 whales have been recorded to examine how social factors shape fertility and survival in the two populations. This programme of research promises to advance our understanding of how natural selection has shaped life history evolution in species that live in close-knit family groups. Our work will provide the first test of the current evolutionary theory for the evolution of menopause in non-human animals and the outputs of this work will provide an informative comparison for the evolution of human life history. More generally, our work will advance our understanding of the ageing process in social species and the interplay between an individual‘s social relationships and its life expectancy.

3. The influence of Social Networks on Health and Productivity in Dairy CattlePrevious work on food production animals has generally ignored how social relationships within a group contribute to productivity and welfare, even though these relationships have been documented to be extremely important for individual health and fitness in wild animal populations. This project is using social network methods to define and quantify the patterning of social relationships within groups of dairy cows with the aim of determining the implications of social network structure for productivity and welfare. The outcomes of this work will provide the UK dairy industry with management advice on how herd social network structure contributes to the health of dairy cows and thus, both the quantity and quality of milk produced. It will indicate how herd social structure can be modified to improve production traits and animal welfare.

4. The influence of Social Networks on Health and Welfare in FlamingosArtificial composition of captive populations and movements of individuals as part of breeding decisions have the potential to impact on the benefits that individuals obtain from being part of a wider social network. When thinking about improving reproductive success, longevity, health and welfare status, evaluating the appropriateness of zoo-based social groups is a useful place to start. This project sets about to understand the pattern of associations (and the importance of such associations) in flamingos which are one of the commonest captive-housed animals kept in zoological collections. Four of the six flamingo species are of conservation concern and captive breeding can be problematic for all species. Flamingos are also very long-lived, giving individual birds within flocks the ability to form long-term, close-knit bonds. These strong bonds may help us unravel the reasons why some birds in some flocks are reproductively active whereas other individuals are not. The outcomes of this work will provide those working with highly social zoo animals, such as flamingos, information on the importance of social stability for positive welfare.

School of Psychology, College of Life and Environmental Sciences, Washington Singer Laboratories, Perry Road, Exeter, Devon, EX4 4QG